Solar photocatalytic degradation of phenol by TiO₂/AC prepared by temperature impregnation method

Abstract

Solar photocatalytic degradation of phenol by TiO₂ (p25), which was immobilized on powdered activated carbon (TiO₂/AC) by temperature impregnation method, was investigated. Solar compound parabolic collectors reactor with a capacity of 4.0 L was used. Characterization of TiO₂/AC by Brunauer–Emmett–Teller analysis, Fourier transform infrared spectroscopy, and scanning electron microscope revealed successful impregnation of TiO₂ particles on activated carbon (AC). Fifty three percent degradation of phenol was recorded at irradiation time of 30 min and increased up to 80% after 150 min using TiO₂. This was not the case for TiO₂/AC, where the phenol was rapidly removed by a value of 40% within 15 min and complete degradation of phenol was attained at illumination time of 120 min. This indicates that immobilization of TiO₂ on AC is very effective for phenol degradation. Moreover, in TiO₂/AC photocatalysis, the presence of aromatic intermediates (catechol, hydroquinone, and p-benzoquinone) was relatively lower as compared to TiO₂ photocatalysis. However, TiO₂/AC photocatalysis of phenol degradation is strongly affected by pH values and dosage of the catalyst, i.e. complete degradation of phenol was occurred at pH value of 5.3 and dosage of 1.2 g/L. The photocatalytic degradation of phenol by TiO₂/AC followed the pseudo-first-order kinetic according to Langmuir–Hinshelwood model. Costs estimation of full-scale solar oxidation plant with life time of 20 years was assessed. The results showed that complete removal of phenol using TiO₂/AC costs 3.19 €/m³.

Keywords:

• Photocatalysis
• TiO₂/AC
• Phenol
• Activated carbon
• Compound parabolic collectors

Acknowledgments

The first author is grateful for the Egyptian Ministry of Higher Education which provided him a full scholarship and for Japan International Cooperation Agency (JICA) for providing all the facilities to participate in this work.